Not a dinosaur, but a furry critter that might have been stepped on or eaten
by one. _Fruitafossor_ comes from the Morrison Formation of Fruita,
Colorado, and is a fascinating creature. And no, this is not an April
Fool's joke. :-)

Abstract: "A fossil mammal from the Late Jurassic Morrison Formation,
Colorado, has highly specialized teeth similar to those of xenarthran and
tubulidentate placental mammals and different from the generalized
insectivorous or omnivorous dentitions of other Jurassic mammals. It has
many forelimb features specialized for digging, and its lumbar vertebrae
show xenarthrous articulations. Parsimony analysis suggests that this fossil
represents a separate basal mammalian lineage with some dental and vertebral
convergences to those of modern xenarthran placentals, and reveals a
previously unknown ecomorph of early mammals."

The authors describe the new genus and species _Fruitafossor windscheffeli_,
a small mammal known from a relatively complete specimen (lower jaws,
incomplete cranium, and nearly 40% of the postcranium, including a complete
forelimb and manus, elements of the hindlimb and pes, and many vertebrae).
_ Fruitafossor_ was a fossorial mammal, with the forelimbs and hands
specialized for scratch digging. The authors propose that it fed on termites
and other insects, as well as plants. The teeth are rather aardvark-like
and the lumbar vertebrae are xenarthrous (to help the vertebral column
resist torsion produced by digging), but the authors are at pains to point
out that both features are convergent upon tubulidentates and true
xenarthrans. The phylogenetic analysis shows _Fruitafossor_ to represent a
unique lineage of basal mammals, a long way from eutherians, and positioned
between the monotreme and triconodont lineages.